In this research, the refinement behavior of the coarse magnesium powders fabricated by gas atomization was investigated as a function of milling time using a short duration high-energy ball milling equipment, which produces fine powders by means of an ultra high-energy within a short duration. The microstructure, hardness, and formability of the powders were investigated as a function of milling time using X-ray diffraction, scanning electron microscopy, Vickers micro-hardness tester and magnetic pulsed compaction. The particle morphology of Mg powders changed from spherical particles of feed metals to irregular oval particles, then platetype particles, with increasing milling time. Due to having HCP structure, deformation occurs due to the existence of the easily breakable C-axis perpendicular to the base, resulting in producing plate-type powders. With increasing milling time, the particle size increased until 5 minutes, then decreased gradually reaching a uniform size of about 50 micrometer after 20 minutes. The relative density of the initial power was 98% before milling, and mechanically milled powder was 92~94% with increase milling time (1~5 min) then it increased to 99% after milling for 20 minutes because of the change in particle shapes.

The ultrafine titanium carbonitride () particles below 100 nm in mean size, including various carbon and nitrogen contents (x=0.55~0.9, y=0.1~0.5), were successfully synthesized by new Mg-thermal reduction process. Nanostructured sub-stoichiometric titanium carbide () particles were initially produced by the magnesium reduction of gaseous at and post heat treatments in vacuum were performed for 2 hrs to remove residual magnesium and magnesium chloride mixed with . Finally, well C/N-controled phases were successfully produced by nitrification heat treatment under normal gas atmosphere at for 2 hrs. The values of purity, mean particle size and oxygen content of produced particles were about 99.3%, 100 nm and 0.2 wt.%, respectively.

This study aims to investigate the optimum conditions (namely pH and Mg2+ concentration) for removing nutrients using MgCl2. I t will also aim to remove high concentrations of nutrients such as those found in wastewater using MgCl2 with the aid of zeolite. I t was observed that nutrient removal using MgCl2 is best at pH 9. Increasing the pH further would affect NH4 + and PO4 3- ions therefore lowering the removal efficiency. Struvite formation does not occur at equal molar concentrations, which may be due to the absence of seeding material. Although addition of zeolite can increase removal effeciency for nitrogen, 100% removal may not be obtained. The Mg2+ previously present affect the ion exchange negatively.

Different types magnesium hydroxide groups have been obtained using the hydrothermal precipitation technique from magnesium sulfate and calcium carbonate solution. The Mg atom coordinated around O atom of SO42- in another layer to form a multi-layer structure crystal. The influence of synthesis parameters on the morphological characteristics and size of magnesium hydroxide groups precipitated in aqueous were investigated such as different of additive and pH. Magnesium hydroxide groups were decomposed gradually and converted finally to MgO particles after heated in air temperature up to 1050℃. The particle size and it's distribution morphology, crystal phase and thermal behavior of the samples were characterized through XRD, SEM, EDS, and TG/DTA.

The ultrafine titanium carbonitride particles () below 100nm in mean size were successfully synthesized by Mg-thermal reduction process. The nanostructured sub-stoichiometric titanium carbide () particles were produced by the magnesium reduction at 1123K of gaseous and the heat treatments in vacuum were performed for five hours to remove residual magnesium and magnesium chloride mixed with . And final phase was obtained by nitrification under normal gas at 1373K for 2 hrs. The purity of produced particles was above 99.3% and the oxygen contents below 0.2 wt%. We investigated in particular the effects of the temperatures in vacuum treatment on the particle refinement of final product.

Magnesium and its alloys are attractive as light weight structural/functional materials for high performance application in automobile and electronics industries due to their superior physical properties. In order to obtain high quality products manufactured by the magnesium powders, it is important to control and understand the densification behavior of the powders. The effect of the sheath surrounding the magnesium powders on the plastic deformation and densification behavior during equal channel angular pressing was investigated in the study by experimental and the finite element methods. A modified version of Lee-Kim's plastic yield criterion, notably known as the critical relative density model, was applied to simulate the densification behavior of magnesium powders. In addition, a new approach that extracts the mechanical characteristics of both the powder and the matrix was developed. The model was implemented into the finite element method, with which powder compaction under equal channel angular pressing was simulated.

Numerical simulations of the powder extrusion need an appropriate pressure-dependent constitutive model for densification modeling of the magnesium powders. The present research investigated the effect of representative powder yield function of the critical relative density model. We could obtain reasonable physical properties of pure magnesium powders using cold isostatic pressing. The proposed densification model was implemented into the finite element code. The finite element analysis was applied to simulation of powder extrusion of pure magnesium powder in order to investigate the densification and processing load at room temperature.

마그네슘 시비농도를 인위적으로 조절하여 '매향' 딸기를 관비재배하면서 Mg의 시비수준이 생장과 결핍증상 발현에 미치는 영향을 구명하고, 건전생육을 유지할 수 있는 식물체 및 토양의 한계농도를 밝히기 위하여 본 연구를 수행하였다. 마그네슘 결핍증상은 하위엽에서 발생하였으며, 초기에 하위엽의 엽맥 사이에서 반점 형태의 황화현상이 나타난 후 점차 반점 부위가 확산되어 엽맥간 황화현상으로 발전하였다 또한 증상이 심해지면서 엽맥 사이가 검게 변하고, 하위엽 선단의 갈변 및 괴사하는 증상이 발생하였다. Mg시비농도를 조절하여 관비하고 정식 120일 후에 지상부 생육을 조사한 결과 Mg 1.0 또는 2mM의 처리에서 생육이 우수하였으며, 0.5 이하나 4mM 이상으로 Mg 시비농도를 조절한 처리의 생장이 저조해지는 경향이었다. 건물중은 마그네슘 시비농도에 대하여 3차 곡선회귀적인 반응을 보였으며 식물체당 약 8.2g의 건물중을 생산할 때 정점이 형성되었다. 최대 생장량의 90%를 최저 한계점으로 간주하면 식물체당 7.4g 이상의 건물중을 생산하기 위해서는 Mg 함량이 0.30~0.65%의 범위에 포함되도록 시비해야 하며, 최적 시비농도는 약 2mM 이라고 판단하였다. 또한, 최대 생산량인 식물체당 생체중 36.2g의 90%를 최저 및 치고 한계점으로 간주 할 경우 엽병 추출액의 Mg농도가 19~40mg·kg-1의 범위에 포함되도록 시비해야 한다고 판단하였다.

Carbon was known to be one of effective additives which can improve the flux pinning of at high magnetic fields. In this study, glycerin was selected as a chemical carbon source for the improvement of critical current density of . In order to replace some of boron atoms by carbon atoms, the boron powder was heat-treated with liquid glycerin. The glycerin-treated boron powder was mixed with an appropriate amount of magnesium powder to composition and the powder pallets were heat treated at for 30 min in a flowing argon gas. It was found that the superconducting transition temperature of prepared using glycerin-treated boron powder was 36.6 K, which is slightly smaller than (37.1 K) of undoped . The critical current density of was higher than that of undoped and the improvement effect was more remarkable at higher magnetic fields. The , decrease and increase associated with the glycerin treatment for boron powder was explained in terms of the carbon substitution to boron site.

The total energy and strength of Mg alloy doped with Al, Ca and Zn, were calculated using thedensity functional theory. The calculations was performed by two programs; the discrete variational Xα (DV-Xα) method, which is a sort of molecular orbital full potential method; Vienna Ab-initio Simulation Package(VASP), which is a sort of pseudo potential method. The fundamental mixed orbital structure in each energylevel near the Fermi level was investigated with simple model using DV-Xα. The optimized crystal structurescalculated by VASP were compared to the measured structure. The density of state and the energy levels ofdopant elements was discussed in association with properties. When the lattice parameter obtained from thisstudy was compared, it was slightly different from the theoretical value but it was similar to Mk, and weobtained the reliability of data. A parameter Mk obtained by the DV-Xα method was proportional toelectronegativity and inversely proportional to ionic radii. We can predict the mechanical properties becauseis proportional to hardness.

Magnesium and magnesium alloys are promising materials for light weight and high strength applications. In order to obtain homogeneous and high quality products in powder compaction and powder forging processes, it is very important to control density and density distributions in powder compacts. In this study, a model for densification of metallic powder is proposed for pure magnesium. The mode] considers the effect of powder characteristics using a pressure-dependent critical density yield criterion. Also with the new model, it was possible to obtain reasonable physical properties of pure magnesium powder using cold iso-state pressing. The proposed densification model was implemented into the finite element method code. The finite element analysis was applied to simulating die compaction of pure magnesium powders in order to investigate the density and effective strain distributions at room temperature.

Ultrafine titanium carbide particles were synthesized by the reaction of liquid-magnesium and vaporized TiCl+CCl(x = 1 and 2) solution. Fine titanium carbide particles with about 50 nm were successfully produced by combining Ti and C atoms released by chloride reduction of magnesium, and vacuum was then used to remove the residual phases of MgCl and excess Mg. Small amounts of impurities such as O, Fe, Mg and Cl were detected in the product, but such problem can be solved by more precise process control. The lattice parameter of the product was 0.43267 nm, near the standard value. With respect to the reaction kinetics, the activation energy for the reactions of TiCl+CCland Mg was found to 69 kJ/mole, which was about half value against the use of TiCl+CCl, and such higher reactivity of the former contributed to increase the stoichiometry until the level of TiC and decrease the free carbon content below 0.3 wt.%.

마그네슘은 20여년간 자동차 산업에서 휠소재로 사용되어 왔다. 마그네슘 휠은 무게가 알루미늄 휠보다 25% 가벼워서 주행성이 우수하다. 이 연구의 목적은 사형주조 및 영구금형주조 공정에 의한 AZ91D 합금제 췰을 개발하는 것이다 보호개스(SF6+CO2)를 사용하는 비플럭스 용해기술을 적용하여 용탕의 산화와 불순물의 유입을 배제하였다 마그네슘 용탕은 가압식 펌프시스템을 사용하여 가열된 파이프를 통하여 모울드에 자동으로 공급된다. 열처리 및 인고트의 조성에 따른 AZ91B 합금제 휠의 기계적 특성을 조사하였다.

In order to investigate of the Influence of Mg2+, Ca2+ on α-linolenic acid converted into the eicosapentaenoic acid(EPA) and docosahexaenoic acid(DHA) forming in plasma lipid and in liver microsomes of rabbit, the animals were fed on the perila oil rich α-linolenic acid or sardine oil rich EPA and DBA diet for 4 weeks were examined. In plasma, liver lipid, Mg2+ was influenced on arachidonic acid(AA), EPA, DHA formative from α-linolenic acid in perilla oil, but stearic acid was increased, Ca2+ was Influenced on stearic acid increased and DHA was decreased. In phospholipid, Mg2+, Ca2+ was influenced on stearic acid increased and DHA was decreased in perilla oil.

봄철에 자라는 목초를 다른 계절의 목초와 비교하면 어떤 특성이 있는지, 또 그 시기의 칼룸질 비료의 시용이 목초의 수분 또는 마그네슘 함량에 어떤 영향이 있는가를 알아보고자 오차드그라스 (Dacctylis glomerala L.) 채초지에서 시험했는데, 그 결과는 칼륨 시용에 따른 무기질과 수분함량에 계절차이가 뚜렷하다는 것이었다 본 시험에서 봄철 (4월)에 생육하는 목초의 무기질함량은 다른 계절보다 큰 변화를 나타냈으며, 칼륨함량은 높고 마그네슘함량은